Total calcium (Ca) and Magnesium (Mg) levels are relatively easily measured using AA, MS or spectrophotometry. Unfortunately, the quantification of clinically relevant ionized Ca and Mg (i-Ca, i-Mg) is more difficult. Currently, i-Ca and i-Mg are measured using potentiometry with ion-selective electrodes (ISE), which is sensitive to physical and biological conditions.
There is a need for alternate measurement options for evaluating clinically relevant ionized constituents in biosamples.